Schema extension of Enhanced Presence categories

Schema extensions for existing enhanced presence categories are made by the schema designer. Using such extensions, the schema designer can update a given category schema from one version to the next.

Schema extensions add additional child elements to existing category. The added elements are in the same namespace of the given category. This type of extension is enclosed by a delimiter element element and an end element element. Multiple delimiter elements can occur and each of the elements marks the beginning of an extension introduced in a particular version.

As an example, the following shows a state[@type='machineState'] element category instance containing a schema extension that was introduced in Microsoft Office Communications Server 2007 R2.